The present invention is related to a full-wave driving circuit for multiple electroluminescent lamps. The full-wave driving circuit is able to drive single or multiple electroluminescent lamps to flash at the same time.
Various kinds of electroluminescent lamps have been applied to may fields. The existing A.C. boosting circuits for driving [a] electroluminescent lamps can be substantially divided into two kinds as follows:
The first utilizes half-wave technique (as shown in FIG. 1A) or transformer for driving the electroluminescent lamp or element. The half-wave technique has a greatest weakness of insufficient illumination. With respect to the transformer, the electroluminescent lamp itself can act as a capacitor which works with the inductance of the transformer, resistors, capacitors and transistors to produce an oscillating signal as the input of the primary terminal of the transformer. The oscillating signal is converted into high voltage A.C. signal at secondary terminal for driving the electroluminescent lamp. Such method can drive the electroluminescent lamp to provide high illumination. However, there are still shortcomings exiting in such method. For example, great electricity is consumed, it is hard to control the quality of the transformer, the whole circuit will expend large space, the manufacturing cost is higher, and it is difficult to mass-produce.
The second utilizes full-wave driver or driving IC to provide signal-switching transistor for driving the electroluminescent lamp (as shown in FIG. 1B). According to the principle that an inductor or a coil is able to store energy, when the transistor is rapidly turned off, the inductor or coil instantaneously discharges the energy to produce instantaneous high voltage. The energy is stored in the electroluminescent lamp via a diode. Such procedure is repeated. After a period of time, another path is energized to produce high voltage signal. Accordingly, high voltage signals are alternately produced at two terminals of the electroluminescent lamp. With one terminal as reference point, the full wave high voltage signal is produced at the other terminal. The electroluminescent lamp driven by such method can improve the shortcoming of the above driving method by way of transformer. However, it will be relatively hard to drive multiple electroluminescent lamps to flash and the circuit design will be more complicated. Also, the components of the circuit are increased and the manufacturing procedure is more difficult.
It is therefore a primary object of the present invention to provide a full-wave driving circuit for multiple electroluminescent lamps. The operating voltage is boosted via a circuit structure composed of the coil, transistors, diodes and switches, whereby the circuit structure serves to drive single or multiple electroluminescent lamps to flash at the same time.
It is a further object of the present invention to provide the above full-wave driving circuit for multiple electroluminescent lamps, by which the illumination of the electroluminescent cells is enhanced. The volume of the driving circuit is smaller than that of the conventional driving circuit and the power consumption is lowered.
The present invention can be best understood through the following description and accompanying drawings wherein: